Vasiliev J M, Gelfand I M, Domnina L V, Zacharova O S, Ljubimov A V
Proc Natl Acad Sci U S A. 1975 Feb;72(2):719-22. doi: 10.1073/pnas.72.2.719.
Contact inhibition of phagocytosis was found to be characteristic for epithelial sheets formed in cultures by several cell types: normal and transformed mouse kidney cells, and differentiated mouse hepatoma cells. In these sheets most central cells surrounded by other cells had very low phagocytic activity. In contrast, marginal cells having a free edge were able to perform an active phagocytosis. Contact inhibition of phagocytosis was absent in dense cultures of mouse embryo fibroblasts and in cultures of anaplastic mouse hepatoma 22a. The upper surface of epithelial sheets was nonadhesive for prelabeled epithelial cells and fibroblasts. In contrast, the upper surface of dense cultures of mouse fibroblasts was adhesive for these cells. These and other data strengthen the suggestion that contact inhibition of phagocytosis is a result of different adhesiveness of the upper cell surface and of the surfaces near the free edge. Agents inhibiting cell surface movements at the free edges of marginal epithelial cells (cytochalasin, azide, sorbitol, low temperature) prevented adhesion of particles to these edges. Possibly, the surface of actively moving cytoplasmic processes is the only cell part that has adhesive properties necessary for the formation of attachments with other cellular and noncellular surfaces. In epithelial sheets, in contrast to fibroblast cultures, Colcemid did not activate movements of immobile contacting cell edges. These results indicate that mechanisms of contact immobilization of cell surface may be different in epithelium and fibroblasts. Firm contacts formed between epithelial cells are sufficient for stable immobilization of the surface; additional stabilization of the surface by microtubules is not essential. Fibroblasts do not form firm contacts and the Colcemid-sensitive stabilization process is essential for maintenance of the immobile state of their surfaces. Differences in the stability of cell surface immobilization produced by cell-cell contacts may also explain different adhesiveness of the upper surfaces of dense fibroblastic and epithelial cultures.
正常和转化的小鼠肾细胞，以及分化的小鼠肝癌细胞。在这些片层中，被其他细胞包围的最中央的细胞吞噬活性非常低。相比之下，具有自由边缘的边缘细胞能够进行活跃的吞噬作用。小鼠胚胎成纤维细胞的密集培养物和间变性小鼠肝癌22a的培养物中不存在吞噬作用的接触抑制。上皮片层的上表面对预先标记的上皮细胞和成纤维细胞无粘附性。相比之下，小鼠成纤维细胞密集培养物的上表面对这些细胞有粘附性。这些及其他数据支持了这样的观点，即吞噬作用的接触抑制是细胞上表面和自由边缘附近表面不同粘附性的结果。抑制边缘上皮细胞自由边缘处细胞表面运动的试剂（细胞松弛素、叠氮化物、山梨醇、低温）阻止了颗粒与这些边缘的粘附。可能，活跃移动的细胞质突起的表面是唯一具有与其他细胞和非细胞表面形成附着所需粘附特性的细胞部分。与成纤维细胞培养物不同，在上皮片层中，秋水仙酰胺不会激活静止接触的细胞边缘的运动。这些结果表明，上皮细胞和成纤维细胞中细胞表面接触固定的机制可能不同。上皮细胞之间形成的牢固接触足以使表面稳定固定；微管对表面的额外稳定作用并非必需。成纤维细胞不形成牢固接触，秋水仙酰胺敏感的稳定过程对于维持其表面的静止状态至关重要。细胞间接触产生的细胞表面固定稳定性的差异也可能解释了密集的成纤维细胞培养物和上皮培养物上表面不同的粘附性。
